Question

[Mai Hang]

tính nhanh 

A = \(\frac{-7}{813}\)+ 496 . (\(\frac{-7}{813}\))  + (\(\frac{-7}{813}\)) . 316

B= \(\frac{-9}{10}\).\(\frac{5}{14}\)+ \(\frac{1}{10}\). (\(\frac{-9}{2}\))+ \(\frac{1}{7}\). (\(\frac{-9}{10}\))

Answer 1

[Lê Tài Bảo Châu]

a) \(A=\frac{-7}{813}+496.\left(\frac{-7}{813}\right)+\left(\frac{-7}{813}\right).316\)

\(=\frac{-7}{813}.\left(1+496+316\right)\)

\(=\frac{-7}{813}.813\)

\(=-7\)

b) \(B=\frac{-9}{10}.\frac{5}{14}+\frac{1}{10}.\left(\frac{-9}{2}\right)+\frac{1}{7}.\left(\frac{-9}{10}\right)\)

\(=\frac{-9}{10}.\left(\frac{5}{14}+\frac{1}{2}+\frac{1}{7}\right)\)

\(=\frac{-9}{10}.1\)

\(=\frac{-9}{10}\)